Journal of Applied Geodesy最新文献

{"title":"Investigating the preparation phase of volcanic eruptions using Swarm and GPS-TEC satellite data: The case of the 29 May 2024 Iceland-Sundhnúkur volcanic eruption","authors":"Mehdi Akhoondzadeh","doi":"10.1515/jag-2025-0010","DOIUrl":"https://doi.org/10.1515/jag-2025-0010","url":null,"abstract":"Abstract In the last 6 months, 5 eruptions have been reported at the location of Iceland’s volcanoes. In this study using the electron density and temperature data measured by the LP sensor onboard the Swarm satellites (A, B, C), the volcanic ionospheric anomalies around the location and time of the Sundhnúkur volcano have been investigated. Most parameters measured by the three Swarm satellites show striking anomalies on 34 and 8 days before the eruption. Also, in this study, GPS-TEC data were used as a volcanic precursor, and median-interquartile method was implemented to detect hidden and highly nonlinear volcano-ionospheric anomalies. This precursor detected clear anomalies in the time interval of 8 days before the eruption. Also, the values of AOD (Aerosol Optical Depth) parameter indicate abnormal behavior on 9 days prior to the event. To reduce the uncertainty of the detected volcanic anomalies, a confutation analysis was also performed, and no clear anomalies were observed in the same spatial and temporal interval studied, but in 2019. The observed anomalies are consistent with geological and seismic reports. For more detailed analysis, we separately investigated the tracks of the satellites crossing the volcano’s buffer zone. Observed anomalies in the time series analysis were acknowledged. Therefore, the results of this study emphasizes that Swarm satellite data, along with other satellite and field data, can be used to predict, detect and track volcanic activities and it is shown that by comparison with other lithospheric and atmospheric precursors, uncertainty in eruption prediction can be reduced.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"20 1","pages":"163-177"},"PeriodicalIF":0.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147917535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Employing variance component estimation for point cloud based geometric surface representation by B-splines.","authors":"Elisabeth Ötsch, Corinna Harmening, Hans Neuner","doi":"10.1515/jag-2025-0037","DOIUrl":"10.1515/jag-2025-0037","url":null,"abstract":"<p><p>When it comes to the significance assessment of interepochal displacements, great reliance on the stochastic information related to the point clouds introduced in the estimation of the geometric representation of the analysed surface is present. Possible uncertainty sources in point clouds are instrument-, environment- or object sided. Further, the chosen mathematical model for point cloud approximation may introduce an uncertainty budget ascribed as model uncertainty. The present contribution employs variance component estimation (VCE) in the course of geometric point cloud approximation with tensor product B-spline surfaces. A method using the BIQUE-estimation of the variance components is used. It enables considering overlapping variance components. Here, those are related to measurement and model uncertainties. The aim of the article is to investigate whether a realistic estimation of the components can be achieved by means of the VCE in particular with regard to the separation between measurement and model uncertainty. The former include the distance and angular components whilst the model uncertainty is set up using covariance functions. For that, a B-spline surface with comparably superior complexity, whilst describing an identical geometric surface course as the functionally employed surface representation, is generated. Artificial altering of the more complex surface establishes the model uncertainty as distance between equally parametrized sampled points. Results based on simulated data show that variance components are separable and estimable if the model uncertainty exceeds measurement uncertainty, and only points affected by model deviations are included in the VCM setup.</p>","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"19 3","pages":"377-384"},"PeriodicalIF":1.2,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12257923/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144643806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring of volcanic precursors using satellite data: the case of Taftan volcano in Iran","authors":"Mehdi Akhoondzadeh","doi":"10.1515/jag-2024-0049","DOIUrl":"https://doi.org/10.1515/jag-2024-0049","url":null,"abstract":"Abstract In recent weeks, there have been reports of gas emanations from the crater of the dormant Taftan volcano in Iran. In this study, due to the limitations of ground stations and the advantages of satellite remote sensing, it has been tried to detect possible anomalies using the plasma data measured by Swarm (A, B and C) and GPS (Global Positioning System) satellites around the location of the mentioned volcano. Also, lithospheric and atmospheric data including OLR (Outgoing Longwave Radiation), water vapor, ozone, relative humidity, surface and air temperature, AOD (Aerosol Optical Depth), sulfur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ) using the Giovanni website in a period of about 5 months, were downloaded and analyzed. Using the median and interquartile method, possible anomalies were detected in the pre-processed time series of the desired parameters. To justify some of the non-volcanic anomalies, synoptic data including precipitation and temperature were prepared from the nearest ground station. By rejecting the possibility that some detected anomalies are related to volcanic activities, hypotheses were presented for other proposed anomalies. As a result of this research, the capabilities of Swarm satellites and GPS-TEC (Total Electron Content) are emphasized in studies related to the prediction, detection and tracking of volcanic activities and it is shown that by comparative comparison with other lithospheric and atmospheric precursors, uncertainty in eruption prediction can be reduced.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"19 2","pages":"227-245"},"PeriodicalIF":0.0,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147909554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal postseismic due to the 2018 Lombok earthquake based on insar revealed multi mechanisms with long duration afterslip","authors":"Annisa Rizky Kusuma, C. Pratama, N. Widjajanti, Yulaikhah, Oktadi Prayoga, Evi Dwi Kurniasari","doi":"10.1515/jag-2022-0036","DOIUrl":"https://doi.org/10.1515/jag-2022-0036","url":null,"abstract":"Abstract The Lombok earthquake in August 2018 triggered a sequential rupture with doublet earthquake up to Mw 6.9. This tectonic activity occurred near the main earthquake due to the decay of residual energy from one event to another. This activity is suspected to be a post-seismic deformation process such as afterslip and viscoelastic. In this paper, we conducted a study to determine the deformation pattern. Each of these processes can be investigated by extracting InSAR observational data. Time series from Sentinel-1 SAR is processed using LiCSBAS as data observation and then compare with the model based on exponential and logarithmic functions. The results of combined logarithmic and exponential fitting suggest the Lombok multi-event earthquakes were influenced by seismic activity from dual-releasing residual energy comprises of afterslip and viscoelastic as a dual mechanism with long duration rather than single mechanism.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"38 11","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139437274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential synthetic aperture radar (SAR) interferometry for detection land subsidence in Derna City, Libya","authors":"Heba Basyouni Ibrahim, Mahmoud Salah, F. Zarzoura, Mahmoud El-Mewafi","doi":"10.1515/jag-2023-0087","DOIUrl":"https://doi.org/10.1515/jag-2023-0087","url":null,"abstract":"Abstract The country of Libya, situated on the Mediterranean fault zone, has a distinctive geodynamic regime due to the interplay between the Eurasian and African plates, which governs its tectonic evolution. In addition to its seismological significance, Libya is characterized by numerous subsidence and slope instabilities in regions with steep terrain. These geological phenomena have significant consequences for the built environment, as they pose an immediate danger to entire towns and essential infrastructure. Furthermore, infrequent weather phenomena, such as intense precipitation and thunderstorms, when coupled with the geological characteristics of some regions and the presence of seismically active terrain, have the potential to trigger landslide and land subsidence, resulting in significant harm to vital infrastructure. The current study utilizes the DInSAR technology to identify distinct subsidence occurrences that were induced by intense precipitation in coastal regions of Libya, specifically in Derna. These areas experienced significant flooding resulting in collapses during September 2023. A total of six pairs of co-event Interferometric Synthetic Aperture Radar (SAR) were utilized to generate displacement maps in the vertical, north-east, and north-west directions for the purpose of analysing the deformations. The aforementioned activities are conducted via Sentinel-1A images, which is freely accessible through the Copernicus program. Additionally, flood-prone zones were defined using Sentinel-1 GRD imagery. The Interferometric processing revealed multiple areas of subsidence. Subsidence rates of up to −14 cm were found in Derna city’s urban cores after flood. The findings suggest that subsidence may have an effect on the flood-proneness of the region of Derna City as Ground subsidence also occurred in the period immediately before the earthquake, at a rate of −14 cm.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"31 11","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139384948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of GNSS ionospheric scintillations in multiple directions over a low latitude station","authors":"Lakshmanna Kuruva, Maheswara Rao Avula, D. S. Achanta","doi":"10.1515/jag-2023-0076","DOIUrl":"https://doi.org/10.1515/jag-2023-0076","url":null,"abstract":"Abstract Analysis of huge data and detection of scintillation events by human visualization is expensive and time consuming process and also unfeasible in real time. In this paper, classical approaches namely Hard, Semi-Hard and Manual annotation rules are used for detection of the scintillations. For this, one week data is acquired from Septentrio PoLaRx5S GNSS scintillation monitoring Receiver corresponding to various constellations. Seven constellations namely GPS, GLONASS, Galileo, SBAS, BeiDou, QZSS and IRNSS-L5 signals during pre-sunset and post sunset hours are considered. The occurrence of scintillations due to pre-sunset and post sunset period by using hard and semi hard detection rules are analysed. It is observed that the occurrence of scintillations is more in post-sunset hours as compared to pre-sunset hours in all constellations. The performances of Semi Hard and Hard detection rules are compared with manual annotation by using confusion matrices statistical parameters namely accuracy, misclassification and precision. Identified scintillation signals coming from the least and worst affected directions. These results would be useful for early detection of scintillation without human inspection of scintillation events.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"40 5","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving the approximation quality of tensor product B-spline surfaces by local parameterization","authors":"C. Harmening, Ramon Butzer","doi":"10.1515/jag-2023-0071","DOIUrl":"https://doi.org/10.1515/jag-2023-0071","url":null,"abstract":"Abstract Freeform surfaces like tensor product B-spline surfaces have been proven to be a suitable tool to model laser scanner point clouds, especially those representing artificial objects. However, when it comes to the modelling of point clouds representing natural surfaces with a lot of local structures, tensor product B-spline surfaces reach their limits. Refinement strategies are usually used as an alternative, but their functional description is no longer nearly as compact as that of classical tensor product B-spline surfaces, making subsequent analysis steps considerably more cumbersome. In this publication, the approximation quality of classical tensor product B-spline surfaces is improved by means of local parameterization. By using base surfaces with a local character, relevant information about local structures of the surface to be estimated are stored in the surface parameters during the parameterization step. As a consequence, the resulting tensor product B-spline surface is able to represent these structures even with only a small number of control points. The developed locally parameterized B-spline surfaces are used to model four data sets with different characteristics. The results reveal a clear improvement compared to the classical tensor product B-spline surfaces in terms of correctness, goodness-of-fit and stability.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"31 11","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139385285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced topographic-geodetic surveys and GNSS methodologies in urban planning","authors":"G. Madimarova, Toleuzhan Nurpeissova, Azhar Ormambekova, Diana Suleimenova, Aizhan Zhildikbayeva","doi":"10.1515/jag-2023-0088","DOIUrl":"https://doi.org/10.1515/jag-2023-0088","url":null,"abstract":"Abstract The relevance of the problem examined is the need for research to ensure the safety and efficiency of construction and operation of utility networks, in light of the rapid development and growth of urban infrastructure. The purpose of this research is to explore and evaluate the application of topographic-geodetic studies in the context of the design and construction of utilities. The methods used include analytical method, classification method, functional method, statistical method, synthesis method. At the preparatory stage of works the schedule of all stages of project implementation was developed, coordinate and height systems accepted in the territory of the settlement, topographic and geodetic materials, general plans, detailed planning plans, and schemes of settlement development were established. Executive surveys, the territory of Aksukent settlement, and other materials and documents identified in the process of preparatory works were collected and analysed. Using an unmanned aerial vehicle (UAV) data of plan-altitude substantiation and aerial photography were obtained, orthophoto map in WGS84 and MSC coordinate system of the Aksukent settlement territory was obtained. To update the data on existing points of the state geodetic network, complexes of geodetic measurements and calculations were performed and parameters (key) of transformation between WGS84 and WCS coordinate systems were obtained. In the course of the field works, deciphering work was performed based on the obtained orthophoto. The inventory of engineering networks was conducted, which included engineering-geodetic surveys of underground and surface engineering networks (sewerage, water supply, gas supply, heating mains), and engineering-geodetic surveys of overhead and underground cable power lines. The results of the survey of the traces of engineering communications on the territory of Aksukent village were agreed with the balance holders of networks JSC “Turkestan Regional Telecommunications Directorate Kazakhtelecom”, JSC “KazTransGas Aimak”, LLP “Sairam Tazalyk”, LLP “Ontustik Zharyk Transit”. The research is of practical significance, as it contributes to the accurate determination of network parameters, identification of potential problem areas and ensuring effective planning and management of engineering projects.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"84 8","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GNSS positioning accuracy performance assessments on 1st and 2nd generation SBAS signals in Thailand","authors":"Phunsap Thari, Thayathip Thongtan, C. Satirapod","doi":"10.1515/jag-2023-0082","DOIUrl":"https://doi.org/10.1515/jag-2023-0082","url":null,"abstract":"Abstract This research evaluates the performance of the first and second-generation satellite-based augmentation system (SBAS) GAGAN and BDSBAS services in Thailand. The study initially analyses GNSS observations from 40 local continuously operating reference stations (CORS) over the past 12 months in 2022, providing initial horizontal and vertical accuracies at 2.03 and 3.66 m respectively with the single point positioning (SPP) mode. The positioning accuracies are 2.27 m horizontally and 2.54 m vertically as of GAGAN, while 2.94 m horizontally and 3.90 m vertically as of BDSBAS with the first-generation system. Since the 1st generation SBAS performance is affected by the ionosphere, especially in the equatorial and auroral regions, the ionosphere-free combination is applied in the SPP algorithm as well as the 2nd generation SBAS with the Dual-Frequency Multi-Constellation (DFMC) capable receivers for BDSBAS only. The SPP accuracies are 1.51 m horizontally and 3.26 m vertically, where the BDSBAS results are 2.16 m horizontally and 4.28 m vertically. Demonstrated results show that the positioning accuracy cannot be improved significantly when applying the 1st generation GAGAN and BDSBAS systems and the 2nd generation BDSBAS system in Thailand due to the low number of common satellites available, especially when using the SBAS outside their ground tracking network; therefore, it is expected to apply the GNSS observation and computed satellite error correction from the regional ground tracking network to enhance the performance of the 2nd generation SBAS. The positioning accuracy result could be achieved at sub-metre level, which will greatly benefit high-accuracy applications such as air, land, and sea navigation in the region.","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"24 2","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138596614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of satellite images terrestrial surface temperature and WVP using GNSS radio occultation data","authors":"Aya M. Megahed, Ibrahim F. Ahmed, Heba S. Tawfik, G. El-fiky","doi":"10.1515/jag-2023-0085","DOIUrl":"https://doi.org/10.1515/jag-2023-0085","url":null,"abstract":"Abstract Land Surface Temperature (LST) and Water Vapor Pressure (WVP) contour maps can be produced using cameras aboard satellites, for instance, under the name “Remote Sensing (RS)”. Satellite image observations should be verified before using based on a reliable data. Global Navigation Satellite System Radio Occultation (GNSS-RO) method is observing accurate Earth atmosphere parameters continuously. In the present research, LST and WVP differences between Landsat 8 (LC08), Sentinel-3 (S3), and MODIS (Terra and Aqua) images and GNSS-RO are assessed in Egypt depending on the satellites operating periods and data availability during the years from 2015 to 2020. Statistically, S3 and Terra have insignificant differences with RO temperature with an average bias of 3.48 °C and 1.47 °C, respectively, but LC08 and Aqua have significant differences with it. For WVP, Aqua and LC08 have insignificant differences with an average bias of 0.02 kg/m2 and 2.31 kg/m2, respectively, but S3 and Terra have significant differences with RO observations. When comparing LC08 LST data to other satellites, it was found that there were insignificant differences between LC08 and S3 as well as Terra. However, significant differences were observed when comparing LC08 LST data to Aqua. Additionally, significant differences were noted when comparing LC08 WVP data to other satellites. In response to these differences, improvement models have been developed to enhance the estimation of terrestrial data through remote sensing, particularly for satellites that exhibited significant disparities when compared to reference observations (RO).","PeriodicalId":45494,"journal":{"name":"Journal of Applied Geodesy","volume":"119 11","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138599674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}